Novel experiments on the dynamics of amphibious craft during surf zone transit

This article presents the results of a comprehensive experimental study of amphibious vehicle dynamics during surf zone transits. The motions and loads of multi-mode vehicles traversing breaking waves is relevant to operators, designers, and simulators seeking to extend the operation of existing and new platforms into the littorals. Here we present the results from a first-of-its-kind experimental campaign to quantify the dynamics of a free-running amphibious model during surf zone transit. The amphibious vehicle studied was the IIHR Model Quadski, a model-scale free-running craft prototyped at The University of Iowa. Testing was conducted in a wave basin facility, equipped with an artificial beach to produce model-scale breaking waves up to heights of 37 centimeters. Vehicle attitudes, wave elevations, and maneuvering inputs were recorded during repetitious crossings of varied wave conditions in outbound, inbound, and oblique transit trajectories. Analysis of high-level statistics and pairwise comparisons show that decreased momentum entering the surf zone from shore resulted in significantly longer transit times and additional wave encounters, even with equal waterjet thrust. Furthermore, vehicle dynamics during seaward transits were considerably larger in amplitude and shorter in period than landward transits.

本文介绍了对两栖车辆在冲浪区行驶过程中动力学的综合实验研究结果。多模式车辆穿越破碎波时的运动和载荷与操作人员、设计人员以及试图将现有和新平台的作业范围扩展到沿海地区的模拟器相关。在此，我们展示了首次此类实验活动的结果，以量化自由行驶的两栖模型在冲浪区行驶过程中的动力学。 所研究的两栖车辆是IIHR模型Quadski，这是一种在爱荷华大学制作的模型比例的自由行驶船只。测试是在一个波浪水池设施中进行的，该设施配备了一个人工海滩，可产生高达37厘米的模型比例破碎波。在向外、向内和斜向行驶轨迹中，车辆姿态、波浪高度以及操纵输入在不同波浪条件的多次穿越过程中被记录下来。 对高级统计数据的分析和成对比较表明，从岸边进入冲浪区的动量减小，即使水射流推力相同，也会导致行驶时间显著延长和更多次遭遇波浪。此外，向海行驶过程中的车辆动力学幅度比向陆行驶大得多，周期也短得多。